Any info on photoco 1.7x tele-extender?

Just picked this one up...anyone know anything about it?...thanx for replying...

HTTP response: NOT FOUND | MIME changed to 'image/png'

My Canon kit 450D/s90; Canon lenses 18-55 IS, 70-210/3.5-4.5....Nikon kit: D610; 28-105/3.5-4.5, 75-300/4.5-5.6 AF, 50/1.8D Nikkors, Tamron 80-210; MF Nikkors: 50/2K, 50/1.4 AI-S, 50/1.8 SeriesE, 60/2.8 Micro Nikkor (AF locked), 85mm/1.8K-AI, 105/2.5 AIS/P.C, 135/2.8K/Q.C, 180/2.8 ED, 200/4Q/AIS, 300/4.5H-AI, ++ Tamron 70-210/3.8-4, Vivitar/Kiron 28/2, ser.1 70-210/3.5, ser.1 28-90; Vivitar/Komine and Samyang 28/2.8; 35mm Nikon F/FM/FE2, Rebel 2K...HTC RE UWA camera

Well here's a quick test shot...shot with my 135/2.8 nikkor @F4...
and this...putting the ef-xtender on rather than a nikkor xtender gives me Av mode (in P)...nice.
full frame res. reduced from 350 to 88 and given USM 300/.2/0

HTTP response: NOT FOUND | MIME changed to 'image/png'

100% crop given USM 300/.3/0

HTTP response: NOT FOUND | MIME changed to 'image/png'

The edges are a bit soft, but to be expected...

My Canon kit 450D/s90; Canon lenses 18-55 IS, 70-210/3.5-4.5....Nikon kit: D610; 28-105/3.5-4.5, 75-300/4.5-5.6 AF, 50/1.8D Nikkors, Tamron 80-210; MF Nikkors: 50/2K, 50/1.4 AI-S, 50/1.8 SeriesE, 60/2.8 Micro Nikkor (AF locked), 85mm/1.8K-AI, 105/2.5 AIS/P.C, 135/2.8K/Q.C, 180/2.8 ED, 200/4Q/AIS, 300/4.5H-AI, ++ Tamron 70-210/3.8-4, Vivitar/Kiron 28/2, ser.1 70-210/3.5, ser.1 28-90; Vivitar/Komine and Samyang 28/2.8; 35mm Nikon F/FM/FE2, Rebel 2K...HTC RE UWA camera